If there were ever a time to be convinced of the importance of rivers, it’s now. Reports from the western United States bring with them alarming images – including Chinook salmon dying en masse in California due to extreme heat and the Colorado River facing a water shortage for the first time in recorded history. Rivers play a critical part in how ecosystems function. They also factor into a number of industries, from generating power to farming to recreation.

Cover courtesy of Islandport Press

Peter Taylor’s book “From the Mountains to the Sea: The Historic Restoration of the Penobscot River” offers a case study in the transformation of one Maine river. As Taylor – who is president of the Harpswell-based Waterview Consulting and has written about travel and the environment– notes very early on, the Penobscot made use of the river for thousands of years before settlers ever arrived. The bulk of the book’s opening pages are given over to writings by Penobscot Nation Tribal Elder Butch Phillips, who offers a concise account of the river’s shifting history and purpose.

Phillips observes that the river’s use for logging and the creation of dams fundamentally changed the character of the region. “The dams not only altered the temperature and flow of the water and flooded fish-spawning areas, they blocked the once-great migration of salmon, shad, sturgeon, and alewife and other fish that were an important food source for The People,” he writes. “The People who once depended on these fish for their sustenance now had to find other means of survival.”

But by the late 1990s, Taylor writes, a number of disparate groups found common ground over a shared desire: to see the population of Atlantic salmon rebound. That led to the establishment of the Penobscot River Restoration Project (or PRRP), which Taylor describes as “an unprecedented collaboration among the Penobscot Nation, six conservation groups, two hydropower companies, and state and federal agencies.” And while the PRRP’s goal was relatively straightforward on paper, the route its constituents took to achieve this goal was more transformational than one might suspect.

“From the Mountains to the Sea” offers a pithy, meticulous account of the PRRP’s actions over the ensuing decades – and the ways in which these actions transformed the landscape around the river and the ecosystem within it. The photographs that accompany the text help to reinforce the work done by the organization – namely, by offering readers stunning images of the restored river, of the fish that now call it home, and of people finding a renewed purpose there. The narrative isn’t suspenseful; rather, it’s an evenhanded and complete account of the large-scale, multi-faceted and multi-decade project.

Taylor describes how infrastructural obstructions to bodies of water can have a substantial effect on the fish living within them. “As people built dams and road culverts, the Penobscot River and its tributaries became obstructed, and fish migration to spawning habitat like lakes and ponds became restricted, often impossible,” Taylor writes. “By the start of the twenty-first century, tributaries like Blackman Stream had been devoid of alewives for nearly two hundred years.”

That might not seem too significant, until you realize that alewives are, as Taylor notes, “the foundation of the food chain.”

Among the trickier elements of the PRRP’s work was eliminating a number of dams on the Penobscot River, which provided electricity to the region. This aspect of the project entailed finding alternative ways to maintain a certain level of energy production, and of determining which dams would and would not adversely affect the migration of fish.

Ultimately, it wasn’t only the fish that benefited from the river restoration. Once the PRRP’s work was complete more fish led to more eagles and ospreys flocking to the area to eat them, for one. The restoration of fish also benefited the state’s ocean fisheries, and offered a greater sense of hope that threats for multiple endangered species might be reversible.

The story of the PRRP is one of an array of groups finding common cause and working to make it a reality. And that points to this book’s larger value – namely, as a case study for how similar transformations might take place elsewhere in our fractious, divided country. The participants and stakeholders represented a wide range of political ideologies – Republicans, Democrats, Independents —  to say nothing of the disparate stakeholder groups. United by their concern for the Penobscot River, they managed to largely succeed in restoring the river. “From the Mountains to the Sea” offers much to study, and it offers hope for a way forward.

New York City resident Tobias Carroll is the author of the books “Political Sign,” “Reel” and the short story collection “Transitory.” He has reviewed books for Bookforum, the Star Tribune and elsewhere.